<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <link rel="stylesheet" href="style.css">
</head>

<body>
    <canvas id="canvas" width="400" height="400"></canvas>
    <textarea id="log"></textarea>
    <script src="utils.js"></script>
    <script>
        window.onload = function () {
            var canvas = document.getElementById('canvas'),
                context = canvas.getContext('2d'),
                log = document.getElementById('log')

            var rect1 = {
                x: Math.random() * canvas.width,
                y: Math.random() * canvas.height
            }
            context.fillStyle = '#000000'
            context.fillRect(rect1.x - 2, rect1.y - 2, 4, 4)

            var rect2 = {
                x: Math.random() * canvas.width,
                y: Math.random() * canvas.height
            }
            context.fillStyle = '#ff0000'
            context.fillRect(rect2.x - 2, rect2.y - 2, 4, 4)

            var dx = rect1.x - rect2.x,
                dy = rect1.y - rect2.y,
                distance = Math.sqrt(dx*dx + dy*dy)
            log.value = "distance: "+distance
        }
    </script>
</body>

</html>